1. Field of the Invention
The present invention is directed to a method for the operation of a digital data transmission network with which control and/or communication data are transmitted, and to a data transmission network operating according to the method.
2. Description of the Prior Art
PCT Application WO 93/21714 discloses a method for the transmission of digital data wherein a control unit and a number of user units are connected to form a ring network. Data blocks having a predetermined number of bit places are communicated in this ring network. These data blocks are also referred to as frame or data packets. There is a useful data part in the data blocks whose bit places are employed in useful channels in the data transmission. For example, digital voice data in telephony, digitized video data and digital data of a data processing system are communicated in the useful channels. Commands are exchanged between the control unit and the user units, or among the user units, via a control channel (command channel).
A disadvantage of this known method is that the useful channels are already allocated to the future applications during design of the data transmission network. A reaction to a momentary requirement which may occur during operation of the data transmission network is possible only to an extremely limited extent.